No cats = Failed emissions test!

[Dr H]

I finally got my car put through an emissions test with no CATs on and it failed!!

results were:

1st test

co 0.97% - fail
hc 57ppm - pass
lambda 1.007 - pass

2nd test

co 0.75% - fail
hc 63 pm - pass
lambda 1.006 - pass

Natural Idle test

co 0.69% - fail

Is there something wrong with the car? What could cause high CO levels (apart from having no CATs). Paul N you suggested that it should easily pass with no CATs, do you know of anyones car that has?

Also I got the definative judgement on whether a car needs CATs for an MOT. If a tester is in doubt get them to call the Vehicle Inspectorate MOT Helpline on 0845 600 5977, I did and was told:

'There is no part of the test that requires the tester to check wether CATs are fitted to a vehicle. The car is only required to pass the emsissions test but it would be unusual if it did without the CATs'. How right they were...............

So now I have to refit my wierd smoking CATs unless anyone can suggest a way of getting the CO levels down

Cheers

Leigh

[Sweeper]

I believe someone on the board said once that you WILL pass MOT test with not cat's if your engine is working properly.

So.....

Any ideas...

In my country we have so pf*cking bad gasoline so that cat's don't live long and it's the reason of mass decat's lately.

[S2central.net]

Now that's annoying - 1st thing I would check is that the IDLE switch is working correctly. Failure of that would mean the ECU doesn't get into idle mode properly.

How is your lambda sensor ?

I can check both with VAG-COM...

Another possbility is the MAF but I doubt that unless you have other running problems.

Another scenario would be a faulty FPR or lack of vacuum into it - resulting in a higher pressure and therefore fuel is higher than it should be.

There are some deCAT'd 3B owners on the forum who have easily passed the MOT emissions test so it is definitely possible.


Paul

[Dr H]

Paul

Lambda is only 850 miles old, genuine bosch article and was reading 1.006 so it's fine yeah

Come to think of it my average MPG might have come down slightly since I changed the lambda. The old one was fine but seeing as I had the turbo off I thought I'd change it. I have checked the blink codes at that shows nothing?

Car runs fine with no prblems at all. There is a VERY small fluctuation in the idle, say 20 rpm now and again. It's always been there. I've never had a car that has a totally steady (and I mean rock steady) idle.

Can I check the idle switch and the Lambda without VAG-COM?

And what is a FPR - fuel pressure reg? How can this be tested?

It just high CO that is the problem is this showing bad combustion, too much fuel? Doesn't really smell of fuel. Although it does smell different than with the CATs on.

Anyone near Sheffield got VAG COM and know how to drive it properly?

Anyone got a set of emissions figures for a decat car? I guess and early 3B would be subject to the 'non CAT' test because of its age, my car is well within the 3.5% HC limit for the 'non CAT' test. Anyone have a post 92 model that passed with no CATs?

Cheers

Leigh

[Audi Parts Guru]

Leigh,what's the mileage of your car ? i may have an idea for you

[akojacko]

leigh my car passed test last year with last owner with no cats on.. he said they have to be on after 1991/2 by law. he found a tester that basically turned a blind eye to the missing cats. i think that officially the cats are suppossed to go back on for the mot , but wot a chore that is. i will have to find someone here to do it for me next year tho. a mate of mine says that his mates with de-catted cossies get thiers done without cats , so some mot testers must rightly or wrongly turn a blind eye.

[valjo]

come in slovenia. i know guys in test center (mot in your country?) who allways allowed me to pass it without cats

[Crawford_S2]

Just a quick thought, if it is possible to pass the emissions on an mot with no cats fitted and the law states they should be fitted, whats to stop an otherwise law abiding citizen removing the cats and removing the insides then replacing the "shell" so it is effectively a straight pipe but looks like a nice pair of legal cats
Not tried it but does anyone think i may work?

[Dr H]

Originally posted by Audi Parts Guru
Leigh,what's the mileage of your car ? i may have an idea for you

55,870 genuine miles - whats the idea you have?

Leigh

[Dr H]

Originally posted by akojacko
leigh my car passed test last year with last owner with no cats on.. he said they have to be on after 1991/2 by law. he found a tester that basically turned a blind eye to the missing cats. i think that officially the cats are suppossed to go back on for the mot , but wot a chore that is. i will have to find someone here to do it for me next year tho. a mate of mine says that his mates with de-catted cossies get thiers done without cats , so some mot testers must rightly or wrongly turn a blind eye.

Ako you don't need to have CATs fitted. See my first post on this - the bit about the MOT helpline.

Leigh

[S2central.net]

Hey Leigh - I just remembered...




Your car was Superchipped and then supposedly removed by QSC. As you know they didn't reset the WG correctly so how do you know they removed the stupid Superchip fuel & timing chip from your ECU ?

AFAIK, Superchips basic principle is to make it richer (which is fundamentally flawed) across the range. Suggest you borrow an ECU from Paul J or another local and get retested - if the CO readings drastically improve on a different ECU (remember Paul J's has an AMD setup with stock fuel/timing) then you will save a lot of potential phaffing about and component testing.

Actually - I could send you my spare ECU if you like for a retest and meantime you send me yours for the homefry fitment (which will also pass MOT).

Let me know...

Would prefer to at least look inside your ECU and ensure the Superchip has been removed.

Cheers,

Paul

[Dr H]

Good thinking Mr N

You have a PM.

Leigh

[audiman]

Paul, the 3B engined cars are NOT subjected to the same test as a later ABY. Pre 08/92 cars must have check at idle and limits are 3.5% CO and 1200ppm HC!!!

Cars registered after 08/92 have to have a basic emissions test or BET test.

The fast idle limits for this test are 0.3% CO and 200 ppm HC. Lamba must be between 0.97 and 1.03

Idle limits are 0.5% CO and 200 ppm HC

I tried my car on the tester to have a look and i got almost the same results as Leigh.

To me is looks like your car is running perfectly, it is only these small amounts of pollutants that the cats are designed to remove.

Look like the cats will have to go back on for MOT test times.

[Dr H]

Tom

I've put the CATs back on last night as I need to get it through it's MOT. Trouble is they smelled like eggs on the first two trips I did (4 miles and then 15 miles) but the next trip (15 miles) they seemed to stop smelling.

Hopefully its just the fact that they were lying around for a couple of months .

Leigh

[Dr H]

Put the CATs back on and had it MOT'd today emissions are now:

CO - 0.04%
HC - 5ppm
Lambda - 1.000

CO at idle - 0.00%

Oh yeah and it passed it's MOT

Leigh